1. Field of the Invention
This invention relates to optical communications and more particularly to a multi-service optical communication network.
2. Description of the Related Art
While Internet Protocol (“IP”) traffic will represent more than 90 percent of the total public communication network traffic by 2002 and communication service providers plan to invest more than $70 billion in core routing and optical transmission equipment to significantly expand their IP/optical backbone networks, revenues from IP services will only approach $25 billion, which represents only a third of the total communication network services revenue pool of $75 billion. This revenue dilemma is primarily the result of extensive competition in the Internet access market, which has essentially resulted in commodity, flat rate pricing. Extensive use of graphics, audio and video content has driven average utilization up significantly, yet the user is charged the same rate. Service providers must add capacity in the network core without any corresponding increase in revenue. The real challenge for service providers is how to generate more revenue from their IP/optical backbones. By taking advantage of the latest advances in IP quality of service (“QoS”), multiprotocol label switching (“MPLS”), and service transformation technology (the conversion of non-IP services to IP), service providers can evolve dedicated IP infrastructures into a multi-service network architecture, as an alternative to operating separate service-specific networks. The new network architecture is a single multi-service network using IP as the underlying protocol for all service delivery. This allows service providers to supplement IP revenues with other established network service revenues from frame relay, TDM private lines and ATM, resulting in faster payback of the tremendous carrier investment in their IP/optical networks.
However, the multi-service network architecture must have the reliability of the networks it intends to supplement or replace. Fault tolerance must start at the network edge where services converge. IP edge routers currently deployed at the edges of IP/optical networks only support IP services. These routers have roots in enterprise and are therefore not particularly fault tolerant. When IP edge routers lose their primary control circuitry and operation falls back to a redundant controller, a five- to 15-minute outage ensues while the router relearns the routing states and packet forwarding tables. Such outages, while acceptable in a simple single service IP network, are intolerable in a multi-service network architecture. Therefore there is a need for high reliability in the multi-service network.
It is desirable to provide high network availability by providing improved redundancy using a backup link level process in total real time synchronization with an active one in order to enable an expeditious switchover when a failure occurs on the active control card.